Key points

  • Dash 8 cabin could not pressurise due to removal of the recirculation fan previously during maintenance;
  • The unserviceability was not detected by the operator or the flight crew prior to take-off;
  • Operator Maroomba Airlines has taken action to prevent a re-occurrence.

A charter airline has taken a series of safety actions after one of its Dash 8 aircraft took off in an unserviceable state from Perth in 2021, resulting in the cabin failing to pressurise, an Australian Transport Safety Bureau investigation report notes.

On the morning of 20 November 2021, a Maroomba Airlines Dash 8 turboprop left Perth as a charter flight to Port Hedland, Western Australia.

Approaching 10,000 ft after take-off, flight crew observed the cabin had not pressurised. At this altitude oxygen masks were not needed, but attempts to rectify the problem in flight were unsuccessful and the flight crew opted for an immediate return to Perth.

“It was found the aircraft failed to pressurise because its recirculation fan had been removed during maintenance the day prior, and this meant that the cabin was not fully sealed,” ATSB Director Transport Safety Dr Michael Walker said.

The ATSB investigation found Maroomba’s operations personnel incorrectly interpreted a message from the engineering department regarding the aircraft’s maintenance status, and it remained assigned to the charter flight.

“This allocation also remained on the flight crew’s roster and the flight manifest, which contributed to the flight crew’s confidence that the aircraft was serviceable,” Dr Walker said.

“As there were no defects recorded in the aircraft’s defect summary, the captain did not check the maintenance log, which was where the fan’s removal was recorded.

“Also, the captain reset a circuit breaker that had been opened to facilitate the fan removal without fully reviewing the maintenance documentation as per the operator’s flight crew operating manual.”

Since the incident, the operator has taken a range of steps to avoid a recurrence.

These include refining the terminology used by the engineering department to communicate aircraft serviceability, reviewing internal communication methods, and reiterating existing paperwork and circuit breaker resetting requirements.

“All tasks, including those that may seem innocuous, should be performed as though they are the last defence to ensure safe operation,” Dr Walker said.

“The aircraft documents are the primary record of airworthiness, and this occurrence shows that thoroughly checking them remains an important control to determine if the aircraft can be operated.”

Read the report: Cabin pressurisation issue involving a De Havilland Canada DHC-8, VH-QQD, 30 km north of Perth Airport, Western Australia, on 20 November 2021

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